Ultrasonic energy is used to promote mass transfer and chemical reactions in fluid systems for a wide variety of applications. One of these applications is ultrasonic cleaning, in which articles are immersed in a fluid bath while ultrasonic energy is introduced into the bath to enhance the cleaning process. Ultrasonic cleaning systems range from small countertop units used in dental offices and laboratories to large industrial units used in the food and chemical process industries. Ultrasonic cleaning systems also are used in the fabrication of electronic components to remove residues from parts and components following manufacturing steps such as lithography, etching, stripping, and chemical mechanical planarization. In another application, ultrasonic energy is used in sonochemical reactor systems to promote chemical reactions in fluid reaction media.
Many ultrasonic cleaning systems use a fluid bath at atmospheric pressure for immersing articles during cleaning. Other ultrasonic cleaning systems are operated at elevated pressures using pressurized liquids, condensing pressurized vapors, dense fluids, or supercritical fluids to effect cleaning of the articles in a pressurized vessel. Such pressurized ultrasonic cleaning systems are used, for example, in the electronics manufacturing industries to remove residues from parts and components during various fabrication steps. Pressurized ultrasonic processing systems may be used in the chemical industry to promote chemical reactions in sonochemical reaction systems.
Ultrasonic energy can be introduced into fluids by several methods. In one method, ultrasonic generators are submerged in the fluid and operated in situ to generate and transmit ultrasonic energy directly to the fluid. In another method, ultrasonic generators are attached to the outer surface of the vessel walls and the ultrasonic energy is transmitted through the vessel walls and into the fluid. In yet another method, ultrasonic energy is transmitted from external ultrasonic transducers via ultrasonic probes or horns passing through the vessel wall, wherein the ultrasonic energy is dissipated from the horns into the fluid.
The successful operation of high-pressure fluid processes with ultrasonic energy will require careful design of the ultrasonic probes that transmit the ultrasonic energy from an external transducer into the pressurized process fluid in a pressure vessel. There is a need in the art for new and improved designs for these ultrasonic probes and for appropriate seals to secure these probes in pressure vessel walls during pressurized operation.